What do you plan to use the miles for? British Airways has a 40% bonus until 1/31, and BA Avios are great for domestic redemptions (on AA/US flights) and select international redemptions. It's definitely one of the best transfer bonuses Amex offers, but only for the right travel goals. It's true that Amex hasn't had a Delta bonus in several years. I don't know if it's fair to say that "Delta no longer offers that." No one knows the future.